applying force to a rigidbody while keeping magnitude the same

Unity Engine
1

I would like to apply a sideways force to a ball bouncing off a plane that increases the closer to the edge of the plane (I am okay with that part I think!), but when I add the force I want to keep the overall magnitude of the ball the same. How can you do that?

2

Should the applying interval increase or the force itself? If i m not mistaken the force is set by the magnitude so so increasing the force itself wouldn’t make much sense. And if its the interval i don see any problem because it isn’t linked to magnitude?
Maybe i just don’t understand the question.

3

To direclty answer the question:
Get the direction vector (however you need to)
Normalize to make the vector length 1
multiply up the required magnitude
apply force

Force in a direction of specific magnitude… But yeah i dont really get the Q either

4

Thanks for trying to answer my question.

Basically i have ball bouncing around in a frictionless environment so it never loses energy. I have a flat plane. When it bounces closer to the edge of the plane I want to apply a force like the plane was on an angle (but it isn’t) so it bounces off in that direction.

Does that make it any easier to understand?

5

sure.
Not sure how you are applying force to the ball, but you could simply apply an impulse force to the ball at said moment. So it gives a burst of velocity to the ball at any point.

6

That is what i want to do, but i don’t want to speed the ball up.

7

If I understand this correctly, you want the ball to change direction based on the direction of a given force but maintain the same absolute velocity?
Then what you want to do is something like this.

public Vector3 GetNewVelocity(Vector3 ForceDirection,Vector3 CurrentVelocity)
	{
		float velocityMagnitude=CurrentVelocity.magnitude;//store magnitude of current velocity
		Vector3 newVelocity=ForceDirection.normalized*velocityMagnitude;//create new velocity vector in the direction (normalized) of Force with magnitude of velocity
		return newVelocity;
	}

Hope this helps.
cheers
Empo

8

That is correct, thank you :slight_smile:

I will give this a try.

9

did that do the trick for you?